Lead wire protector for resistors and the like



June 29, 1954 B. RUBINSTEIN 2,682,595

' LEAD WIRE PROTECTOR FOR RESISTORS AND THE LIKE Filed May 16, 1952 @sumnum 20 INVENTOR BERTRAM RUBINSTEIN ATTORNEYS Patented June 29, 1954 LEAD WIRE PROTECTOR FOR RESISTORS AND THE LIKE Bertram Rubinstein, Milwaukee, Wis.

Application May 16, 1952, Serial No. 288,227

4 Claims.

This invention appertains to electrical resistors and more particularly to a new and novel resistor unit in which the humidity proof coating and lead wires are protected from rupturing or breakmg.

Most standard, present day, electrical resistors usually include a core of insulation material such as asbestos over which is tightly wound the resistor wires. The resistor Wire is usually of a thin or fine type and the resistance of the resistor is determined by the number of windings,

thickness and the particular material of the wire. In order to insert or connect the resistor element to the electrical circuit in which it is desired to be used, flexible relatively thick lead wires are used and these lead wires are in electrical contact with the resistor wire or element usually by being affixed to a metal cap or clip which in turn is tightly fitted or pressed about the respective ends of the resistor wires.

One of the foremost problems in resistor units is due to the effect that moisture and humidity have on the resistance value of the resisting element as under most circumstances it is necessary for the resistor to be able to maintain a steady resistance in a given electrical circuit. In use, the resistor wire becomes highly heated and any moisture which comes in contact with the wire will cause an undesirable variance in the resistance of the resistor with often times damaging results to the whole electrical circuit 1 and apparatus involved. Therefore, it has been the practice in the past to provide some sort of coating over the entire resistor unit in an effort to make the same moisture proof. However, in applying the resistors to the circuit proper the lead wires must be moved or bent and invariably this prolonged movement results in the fracturing or rupturing of the coating and therefore, moisture may penetrate and come in contact with the resistor wire causing the undesired variance in its capacity and short circuiting of the element.

Another danger lies in the fact that the lead Wires are usually affixed by soldering, or other means, at one point to the cap or clip and often times the lead wire will break at this point while it is being bent to aflix the resistor element to the circuit.

It is therefore, a primary object of my invention to provide an electrical resistor with novel means including protector elements for the lead wires, whereby, the lead wires may be bent in any desired position without the danger of fracturing or breaking either the humidity proof coating or the lead wires per se.

Another important object of my invention lies in constructing my novel protector elements in the shape of tubes or sleeves which are affixed to a respective end terminal of the resistor element and through which the lead wires extend, thereby, strengthening the lead wires and preventing their movement below the top edge of the tubes.

A further object of my invention is to provide a novel humidity proof coating for the resistor unit which extends from the top edge of the tube or sleeve downwardly and completely over the entire unit.

A still further object of my invention is to provide a sealing means within the protector tubes whereby the interior of the tubes are rendered completely sealed from the effects of outside temperatures and humidity changes.

Still another object of my invention is to provide a resistor unit of a simple, practical and reliable construction that is economical to manufacture, easy to assemble and positive in its operation and which will present a relatively smooth and pleasing appearance without objectionable protuberances.

With the above and other objects in view, which will more readily appear as the nature of the invention is better understood, the same consists in the novel construction, combination and arrangement of parts hereinafter more fully described, illustrated and claimed.

One preferred and practical embodiment of my invention is shown in the accompanying drawings, in which:

Figure 1 is a rear elevational view of my new and novel electrical resistor showing in full and dotted lines, two possible positions of the lead wires;

Figure 2 is a rear elevational view similar to Figure 1 of the drawings but with certain parts being broken away to illustrate further details of construction;

Figure 3 is a transverse sectional view through my resistor unit the section being taken on the line 3-3 of Figure 2 and looking in the direction of the arrows;

Figure 4 is a rear elevational view of my assembled resistor unit before the humidity proof coating has been applied; v

Figure 5 is a front elevational view of my assembled resistor unit before the humidity proof coating has been applied;

Figure 6 is a perspective view of one of the end terminal assemblies prior to its being applied about the resistor core and illustrating in 3 particular a lead wire my protector tube or sleeve in place;

Figure 7 is a sectional. View through the end terminal assembly shown in Figure 6, the secti i being taken on the line 'l-"i oi? 6 looking in the direction oi tl arrows and showing how the solder not only aids in holding the protector tube and the l wire to the end ter nal clip, but also how it oils and the interior oi the tube;

Figure 8 is a fragmentary end view in perspective showing the metal terminal clip pressed about the resistor wire but before the protector tube element and solder have been applied.

Referring to the drawings in detail wherein similar reierence characters correspendin parts throughout the several views, the letter enerally indicates one type of my improved resistor and the same includes broadly the hut the outwardly extending lead wires ii and Ii. As illustrated in i: sure 1 of the drawings, the lead wires ii and is may be moved and bent to any desired ion necessitated in affixin the resistor unit (.0 an electrical circuit (not shown).

resistor element per is of a standard construction having core it, of any desired insulated and heat resisting material such as asbestos, about which is tightly wound the resistor ire i l. Ccnventionally, each end of the wound core l is provided with end terminals and while they may be any type, size or shape, I prefer to use metal clips it and it? respectively. Each end terminal is identically formed from a single length of metal bent in the form of a U and as shown. more particularly, in Figure 6 and 7 of the drawings, the end terminal clip it includes an intermediate section l'i carrying de pending legs is and Secured to the portion ll of the end clip H5 i the lead wire ii as shown. The lead wire it may secured in any desired manner such as soldering or as shown, in the preferred for-in, by slipping the end to or the wire through the eye Til which is struclr. up from the portion ll of the U-shaped clip and. then applying the solder. Each end terminal -bly may be assembled and affixed to the respective end or the wound core is by any number or methods. Gne method shown 'rigures 6 and l of the drawings is to slide my novel protector tube or sleeve 23 over the lead wire and firmly solder the same to the U-shaped clip iii. In so doing I fill the protector tube with solder and the same flows in and around ti .1 lead wire and. into the space made by the eye ill. Thus, the lead wire ll is not only firmly soldered. to the end clip ill but is also threaded under the struck up eye 2i and it is to be particularly noted that the solder completely fills the inside of the protector tube or sleeve The reason for this will be more fully indicated. as the description proceeds.

The end terminal clip it is thus fitted over the respective end of the wound core and the ends of the depending legs it and it are bent around and firmly pressed into the rear surface it of the core is as shown more particularly Figure l.

It is to be understood that while I have described in particular the construction of end terminal clip iii, that the end terminal clip i6 is identically formed and lead wire it is affixed thereto in an identical manner to extend through the protector tube M.

It is also apparent that I may press the end .uity proof resistor body it) and clips about the respective ends of the core l3 before I solder the protector tubes in place. This method is illustrated more particularly in Figure 8 of the drawings. The end clip l9 and afiixed lead wire ii are first secured to the respective end of the core I? after the end terminal assemblies are in place and the protector tube 24 is then in the same manner as above described.

I next apply my humidity proof coating 26. This may be done by dipping the entire unit into the coating proper or building up the coating by spraying or the like on the unit. The coating covers the entire resistor unit and extends upwardly and completely around each or the protective sleeves and M terminating just short of the top surfaces thereof. It can thus be seen that any movement of the lead wires II or it can not be transmitted to the coating to fracture or harm the same in any manner.

While it is not necessary, in the preferred form the solder 25 protrudes abovethe coating and top surface or the sleeves and shown best in Figure 3 of the drawings, and the same completely surrounds the lead wires. This forms a more complete seal and eliminates some of the strain on the top of the tube or sleeve proper.

While any type of solder be used, I prefer to use a high temperature solder, preferably one that is solid at 500 F. and liquid at 590 F. This is a sufficiently high temperature to prevent the solder from melting as a result of the heating of the resistor wire l l when the same is applied to an electrical circuit.

A salient feature of my invention resides in the fact that, not only do the protector tubes or sleeves 23 and ti l prevent the breaking or rupturing of the outer coating to due to movement of the lead wires H and i2, but the tubes will also aid in absorbing shock and vibrations.

If desired, I also provide each tube 23 and 24 With a circumferential protuberance fil which serves to further iinbed the protector tubes firmly in the coating 25. For example, should for some reason one or the protector tubes work free from its end terminal clip, it would still be firmly held. by the protuberance extending into the hard coatin and therefore could not be pulled outwardly from the unit.

My protector tubes could also be applied to electrical fuses or the type havin lead wires soldered to end terminal caps or clips but not having a protective coating of any type.

From the foregoin it is believed that the features and advantages of the invention will be readily apparent to those skilled in the art, and it will, of course, be understood that changes in the form, proportions minor details of construction may be resorted to without departing from the spirit or the invention or the scope of the appending claims.

I claim:

1. A resistor unit including an insulated core, a resistance element about said core, pair of end terminals each secured to a respective end of the resistance element, a oi bendable lead wires each secured to a respective end terminal at its inner end and extending outwardly there from, a pair of protector sleeves each secured to a respective end ..rn:inal adjacent the point Where the lead wire is secured to the end terminal and through which the lead wire extends, said protector sleeves terminating substantially short of the outer ends of said lead wires, and

means for rigidly securing the lead wires to the protector sleeves for the entire length of said sleeve.

2. A resistor unit including an insulated core, a resistance element about said core, a pair of end terminals each secured to a respective end of the resistance element, a pair of bendable lead wires each secured to a respective end terminal at its innerend and extending outwardly therefrom, a pair of protector tubes each secured to a respective end terminal adjacent the point where the lead wire is secured to the end terminal and through which the lead wire extends, said protector tubes outer ends terminating substantially short of the outer ends of said lead wires, the interior of said tubes about said lead wires being completely filled with solder, and a humidity proof coating completely surrounding the resistor unit but terminating just short of the outer ends of the protector tubes, whereby the entire unit is rendered humidity proof and movement of the lead wires will not fracture or rupture the coating.

3. A resistor unit including an insulated core, a resistance element about said core, a pair of end terminals each secured to a respective end of the resistance element, a pair of bendable lead wires each secured to a respective end terminal and extending outwardly therefrom, a pair of protector tubes each being secured to a respective end terminal at a point spaced from and adjacent to the point where a respective lead wire is secured to said end terminal, each of said lead wires extending entirely through a respective protector tube and terminating at a point well beyond the outer end of said tube, the

interior of said tubes about said lead wires being completely filled with solder, and a humidity proof coating completely surrounding the resistor unit but terminating just short of the outer ends of the protector tubes, whereby the entire unit is rendered humidity proof and movement of the lead wires will not fracture or rupture the coatmg.

4. The combination of a resistor unit of the type having an insulated core, a resistance element, a pair of end terminal clips pressed around said resistance element and core adjacent each end thereof, a pair of bendable lead wires secured to a respective end terminal clip and extending outwardly therefrom and a protective coating over the entire unit, of a pair of protector tubes each rigidly secured to a respective end terminal clip and extending outwardly with the respective lead wire but terminating substantially short of the outer end thereof, a protective coating covering a portion of each protector tube, and means including high temperature solder completely filling the inside of the tubes for sealing the unit against the effects of moisture and humidity.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,987,489 Mucher Jan. 8, 1935 2,508,511 Goodman May 23, 1950 FOREIGN PATENTS Number Country Date 325,142 Germany Dec. 25, 1917 

